Method of manufacturing a fan assembly

ABSTRACT

In one aspect, a fan assembly is provided that can be manufactured while producing a significantly reduced amount of scrap material. More specifically, the fan assembly utilizes a hub ring and one or more hub strips to support a plurality of blades rather than a solid center disc or end disc used by some prior approaches. In another aspect, a method is provided that includes bending a member into an annular configuration and joining end portions of the member together to rigidly fix the member in the annular configuration. The rigid annular member may be used as an end ring, a hub ring, an orifice, or other component, while producing significantly less scrap material than traditional approaches.

FIELD

The field relates to fans and, more particularly, to fan assemblies forhandling airflow.

BACKGROUND

Centrifugal or forward curved blower wheels may generally comprise aplurality of blades arranged in the form of a cylinder around a solid,central hub disc. During manufacture of a centrifugal blower wheel, astamping press may be used to form the plurality of blades from a metalsheet. The sheet is gathered between the ends of adjacent blades toreduce the distance between the blades. The sheet, with the materialgathered between the blades, is then shaped into a cylinder about thesolid, central hub disc. Because the blades are stamped from a singlemetal sheet, the number of blades and the chords of the blades arelimited by the size of the blades and the size of the sheet.

The solid, central hub disc of the centrifugal blower wheel may beformed by stamping a pair of discs from respective rectangular pieces ofsheet metal, removing the scrap material for recycling, and joining thediscs together. A centrifugal blower wheel may also have one or more endrings deformed onto ends of the plurality of blades to fix the blades inthe cylindrical arrangement about the central hub disc. Like the centralhub disc, the end rings may be formed by stamping circular rings fromrectangular pieces of sheet metal and removing the scrap material forrecycling. Stamping the one or more end rings generates additional scrapbecause each end ring has a central opening formed by removing acircular disc from the center of the end ring. In one approach, thescrap material removed from an end ring to form the central opening canbe used as a solid, central hub disc for the centrifugal blower wheel.Although scrap material produced during manufacture of the centrifugalblower wheel may be recycled, the value of the recycled material may notcompensate for the costs incurred in cutting, storing, and handling thescrap material.

Mixed flow fans, backward inclined wheels, backward curved wheels, andother centrifugal wheels may have a back disc and an end ring that areboth stamped from rectangular pieces of metal, like the central hub discand end ring(s) of centrifugal blower wheels. Because the back disc andthe end ring have a generally circular shape, stamping the circularshapes from rectangular pieces of sheet metal produces scrap in the formof the corner portions of the sheet metal and a circular disc from thecenter of the end ring. Similarly, traditional approaches for producinga venturi or orifice for a fan assembly or a fan housing includestamping a generally ring-shaped orifice from a rectangular piece ofmetal. Even if the scrap circular disc from the end ring or orifice isused to produce a back disc, the corner portions of the sheet locatedoutside of the end ring or orifice would still constitute a large amountof scrap material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a fan assembly;

FIG. 2 is a flow diagram of a method of manufacturing the fan assemblyof FIG. 1.

FIG. 3 is a perspective view of the fan assembly of FIG. 1 with all buttwo fan blades removed;

FIG. 4 is an exploded perspective view of a hub assembly of the fanassembly of FIG. 1;

FIG. 5 is a perspective view of a fan blade of the fan assembly of FIG.1;

FIG. 6 is a side elevational view of the fan blade of FIG. 5;

FIG. 7 is an exploded perspective view of another fan assembly with onlyone blade shown for clarity;

FIG. 8 is a flow diagram of a method of producing parts of fanassemblies and other components;

FIGS. 9-13 are perspective views of a ring forming sub-method of themethod of FIG. 8;

FIGS. 13A and 13B are perspective views of rings formed using thesub-method of FIGS. 9-13;

FIG. 14 is a top plan view of an orifice;

FIG. 15 is a side elevational view of the orifice of FIG. 14; and

FIG. 16 is a perspective view of another fan assembly.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In one aspect, a method is provided that minimizes the amount of scrapmaterial produced during manufacture of blower wheel or fan assembliesand related components. Rather than stamp circular parts fromrectangular sheets of metal, as in traditional approaches, a narrowstrip of material is advanced from a coil and bent along a longitudinaledge of the strip to form a helix. An open annular member is cut fromthe helix and trimmed as needed before the ends of the open annularmember are joined together to form a rigid, annular member. The rigidannular member may be used in place of traditional orifices and fanassembly end rings, to name a few applications. Further, by joining therigid, annular member with one or more hub strips to produce a hubassembly, the rigid annular member may be used in place of central orend discs of traditional fan assemblies.

In another approach, a fan assembly is provided that minimizes theamount of scrap material produced during manufacture of the fanassembly. More specifically, the fan assembly does not utilize a soliddisc traditionally used as a center or end disc for blower wheels, mixedflow fans, or other centrifugal air moving devices. Instead, the fanassembly has a hub assembly comprising a hub ring and one or more hubstrips. Each hub strip has an attachment portion connected to the hubring and a body portion extending radially inward from the attachmentportion. The one or more hub strips are configured to connect directlyor indirectly to a motive source, such as an electric motor, a diesel orgasoline engine, or a turbine, using known mechanical linkages. In oneapproach, the one or more hub strips are connected to a hub that isfixed to a driveshaft of an electric motor. In another approach, the oneor more hub strips have a mounting point or feature for attachment to ashaft or clamp. As is apparent, the hub assembly transmits rotation fromthe motive source to the fan assembly without the use of a solid disc,as in traditional fan assemblies.

Turning to the Figures, FIG. 1 illustrates a fan assembly 10 thatproduces a minimal amount of scrap material during production. The fanassembly 10 has a hub 12 for engaging a motor drive shaft (not shown)and transmitting rotation of the drive shaft to the fan assembly 10 suchthat the fan assembly 10 rotates about an axis of rotation 14. The hub12 is part of a hub assembly 16 that includes the hub 12, one or morehub strips 18, 20, and a hub ring 22. The hub strips 18, 20 connect thehub 12 to the hub ring 22. In an alternative embodiment, the hub 12 isintegrally formed with the hub strips 18, 20.

The hub ring 22 has a plurality of attachment points, such as slots 24,for engaging a plurality of fan blades 26. Each fan blade 26 extendsbetween a pair of end rings 28, 30 and through an associated slot 24 inthe hub ring 22. The hub ring 22 and end rings 28, 30 are each formedfrom an elongate member, such as a strip of material, bent into anannular configuration with respective line welds 23, 25, 27 fixing therings 22, 28, 30 in their annular configuration, as will be discussed ingreater detail below. The hub strips 18, 20, hub ring 22, and end rings28, 30 may be formed from steel, aluminum, or galvanized steel, amongother materials. In alternative approaches, the hub ring 22 and the endrings 28, 30 may be fixed in an annular configuration without line welds23, 25, 27, such as by features integral to the rings, spot welding,parent metal fastening, or mechanical fasteners.

In one approach, each fan blade 26 has a pair of tabs 32, 34 extendingthrough respective slots 36, 38 in the end rings 28, 30. The tabs 32, 34are bent downward against the end rings 28, 30 to fix the blades 26 tothe end rings 28, 30. In alternative embodiments, the fan assembly 10may be a single-inlet type fan assembly with a hub ring 22 and only oneend ring 28. Alternative embodiments may also include attachment pointssuch as rivets or welds that connect the blades 26 to the hub ring 22and end ring(s) 28 (and 30) without the use of tabs or slots. Forexample, a Fergas peening process may be used to connect the blades 26to the end ring(s) 28 (and 30).

FIG. 2 illustrates a method 41 of manufacturing the fan assembly 10while producing a minimal amount of scrap material. The method 41includes producing the hub assembly 16 and the end rings 28, 30 at step43. For some embodiments of the fan assembly 10, such as a single-inletblower wheel, only one end ring will be produced. The plurality ofblades 26 are manufactured at step 45 with a profile that allows the fanassembly 10 to flow air more efficiently, as will be discussed ingreater detail below. The hub assembly 16, end rings 28, 30, and blades26 are then assembled at step 47 to produce the fan assembly 10.

Turning to further details of the fan assembly 10, FIG. 3 illustratesthe fan assembly 10 with all but two blades 26A, 26B removed to show thepositioning of the hub assembly 16 between the end rings 28, 30. One ofthe blades illustrated, blade 26A, extends between the end rings 28, 30with tabs 32A, 34A extending through respective slots 36A, 38A. Blade26B is connected to the hub ring 22 and the end rings 28, 30 byadvancing a tab 34B through slot 24B in the hub ring 22 until the tab34B passes through slot 38B in the end ring 30. A tab 32B of the blade26B is then advanced through a slot 36B in the end ring 28 before thetabs 32B, 34B are bent downward against the end rings 28, 30 to fix theblade 26B to the end rings 28, 30. To fix the blade 26B to the hub ring22, an embossing process forms ridges (not shown) in the blade 26B alongpaths 42, 44 on either side of hub ring 22 to restrict the hub ring 22from sliding along the blade 26B. A similar procedure may be performedto install the remaining blades 26 of the fan assembly 10.

In an alternative approach, each slot 24 of the hub ring 22 extends allthe way to an outer edge 46 of the hub ring 22. With this configuration,the blade 26B may be connected to the hub assembly 16 and the end rings28, 30 by passing a center portion 48 of the blade 26B through the slot24B in a radially inward direction toward the axis 14. The blade 26B isthen manipulated to advance tabs 32B, 34B through respective slots 36B,38B before the blade 26B is secured to the hub ring 22 and the end rings28, 30 as described above.

As shown in FIG. 3, the hub strips 18, 20 include attachment portions56A, 56B and 58A, 58B, respectively. With reference to the attachmentportion 56A, the attachment portion 56A includes tabs 60, 62 that arewelded to the hub ring 22. The tabs of the hub assembly 16 are sized tofit between the slots 24. Although the attachment portions 56A, 56B,58A, 58B are illustrated with tabs for welding to the hub ring 52, theattachment portions 56A, 56B, 58A, 58B may connect to the hub ring 22using any number of approaches, including but not limited to nuts andbolts, rivets, spot welds, line welds, and parent metal fastening.

Turning to FIG. 4, an exploded view of the hub assembly 16 isillustrated. The hub 12 has a through bore 80 aligned with the axis ofrotation 14 for receiving a motor drive shaft (not shown) and an opening82 for receiving a set screw (not shown) which secures the hub 12 to themotor drive shaft. The hub 12 may be cold headed from wire, machinedfrom 12L14 steel bar stock, or any other acceptable manufacturingprocess and/or material. The hub 12 is generally received withinopenings 84, 86 of the hub strips 18, 20 and is connected to the hubstrips 18, 20 using, for example, an orbital press, swedging, and/orstaking.

The hub strip 18 includes a body portion 88 extending between theattachment portions 56A, 56B. In the illustrated embodiment, the hub 12is a separate component from the hub strips 18, 20 and the hub strips18, 20 have features for aligning the hub strips 18, 20 and receivingthe hub 12. More specifically, the body portion 88 includes a hubmounting portion 90 having a concave seat 92 that tapers downward towarda circular flat 94 extending about the opening 84. Similarly, the hubstrip 20 has a body portion 96 extending between attachment portions58A, 58B. The body portion 96 has a hub mounting portion 98 with aconcave seat 100 and a circular flat 102 that are complimentary to theseat 92 and the flat 94 of the hub strip 18 such that the hub mountingportions 90, 98 may nest together when the hub assembly 16 is assembled.Alternatively, the hub mounting portions 90, 98 may be flat and lackseats 92, 100 or other structures that nest together.

The hub ring 22 defines a central opening 110 having a center point 112aligned with the axis 14, as shown in FIG. 4. The hub ring 22 has anouter radius 114 and an inner radius 116 that define a width 113 of thehub ring 22. When the hub strips 18, 20 are connected to the hub ring22, the body portions 88, 96 extend across the central opening 110 andprovide a rigid connection between the hub 12 and the hub ring 22.

As shown in FIG. 5, the blade 26 has a body portion 130 with a pair ofopposed end portions 132, 134. The blade 26 has an outlet portion 140with an outlet angle and an inlet portion 142 with an inlet angle.Preferably, the outlet angle is different than the inlet angle, althoughthe outlet portion 140 and the inlet portion 142 may have similarangles. In the illustrated embodiment, the blade 26 has a compoundradius design, with the outlet portion 140 and inlet portion 142 eachhaving a different radius of curvature, although other embodiments mayhave a similar radius of curvature for portions 140, 142. The blade 26moves more air than traditional fan blade designs for a given bladesize, which allows a fan assembly utilizing the blade 26 to have fewerblades while flowing the same amount of air as traditional fanassemblies. Conversely, a fan assembly utilizing the blade 26 and havingthe same number of blades as a traditional fan assembly will flow agreater amount of air and generate a higher static pressure than atraditional fan assembly.

The blade 26 may be formed using, for example, roll forming or stamping.To control consistency during mass production, the blade 26 may beembossed after forming to limit spring-back of the blade 26 and providemore consistent tolerances of the blade 26. Further, the blade 26 may bemade from a number of materials, including but not limited to galvanizedsteel, aluminum, and plastic. For plastic blades, a rigid or semi-rigidplastic may be chosen, such as polypropylene. A plastic blade may bemolded or extruded.

As shown in FIG. 6, the blade 26 extends between an outlet tip 150 andan inlet tip 152 that travel along an outer diameter 154 and innerdiameter 156, respectively, as the fan assembly 10 rotates. In oneapproach, the outer diameter 154 is in the range of approximately 9.66inches to approximately 11.80 inches, preferably 10.73 inches. A ratioof the outer diameter 154 to the inner diameter 156 is preferably withinthe following range:

$1.0 < \frac{{Diameter}_{154}}{{Diameter}_{156}} \leq 2.0$

In other approaches, the diameters 154, 156 may be increased ordecreased with corresponding adjustments to the other dimensions of theblade 26 to accommodate different applications of the blade 26. Theoutlet portion 140 of the blade 26 extends inward from the outlet tip150 along a plane 158. The plane 158 is oriented at an angle 160relative to the outer diameter 154, the angle 160 being in the range ofapproximately 100° to approximately 180°, preferably 160°. The outletportion 140 converges with a plane 164 that extends parallel to a plane174. A blade camber distance 168 separates the plane 164 from the plane174, the blade camber distance 168 being in the range of approximately0.150 inches to approximately 0.375 inches, preferably 0.287 inches. Theplane 174 extends a chord distance 176 between the tips 150, 152. Thechord distance 176 is in the range of approximately 0.890 inches toapproximately 1.088 inches, preferably approximately 0.989 inches. Aratio of the chord distance 176 to the blade camber distance 168 ispreferably within the following range:

$1.5 \leq \frac{{Distance}_{176}}{{Distance}_{168}} \leq 10.0$

Given this chord/camber ratio and the chord distance 176, the bladecamber distance 168 for a desired chord/camber ratio may be calculatedby dividing the chord distance 176 by the desired chord/camber ratio. Aplane 180 generally extends along a radius of the diameters 154, 156,and intersects blade tip 150. The plane 174 is oriented at a bladesetting angle 166 relative to the plane 180. The blade setting angle 166is in the range of approximately 10° to approximately 40°, preferablyapproximately 27.4°. An inlet portion 142 extends away from the plane164 and converges with a plane 170 at the inlet tip 152. The plane 170is oriented at an angle 172 relative to the inner diameter 156, theangle 172 being in the range of approximately 45° to approximately 70°,preferably 63°. Given the outer diameter 154, the ratio of the outerdiameter 154 to the inner diameter 156, and the blade setting angle 166,the chord distance 176 can be determined using the following equation:

${Distance}_{176} = {{\frac{{Diameter}_{154}}{2}{\cos\left( {Angle}_{166} \right)}} \pm \sqrt{\left( \frac{{Diameter}_{156}}{2} \right)^{2} - {\left( \frac{{Diameter}_{154}}{2} \right)^{2}{\sin^{2}\left( {Angle}_{166} \right)}}}}$

Another embodiment of a fan assembly 300 having a hub assembly 302 isshown in FIG. 7. The fan assembly 300 is similar to the fan assembly 10,with the exception that the hub strips 304, 306 have attachment portions308A, 308B and 310A, 310B which lack tabs for engaging a hub ring 312.Instead, the attachment portions 308A, 308B and 310A, 310B have slots313, 314 which align with slots 316 of the hub ring 312. To secure thehub strips 304, 306 to the hub ring 312, each blade 318 is passedthrough one of the plurality of slots 313 (or 314) and one of theplurality of slots 316 before ridges are embossed in the blade 318 tofix the hub strip 304 (or 306) and the hub ring 312 between the ridges,as discussed above with respect to fan assembly 10. The hub strips 304,306 may alternatively be connected to the hub ring 312 using welds,rivets, or other approaches. Further, slots 313 (or 314) and the slots316 may extend to an outer edge 319 of the hub ring 316 to accommodateradial insertion of the blades 318, as discussed above.

FIG. 8 illustrates a method 400 of producing a product, such as the endrings 28, 30 or the hub assemblies 16, 302 of the fan assemblies 10,300, while generating a minimal amount of scrap material. The method 400comprises a ring forming sub-method 402, explained with reference toFIGS. 9-13B, and a finishing sub-method 404, explained with reference toFIGS. 1 and 14-16. Although the method 400 is described in steps, itwill be appreciated that the steps may be modified, combined, removed,or performed in a different order than the order presented. Further,additional or fewer actions may be performed at each step withoutdeparting from the teachings of this disclosure. If the method 400 isused to produce an orifice, end ring, or hub assembly, the method 400provides a material yield of nearly 100%, which is at least a 33%improvement over traditional processes.

In one approach, the method 400 utilizes a ring forming device 500,shown in FIG. 9, to shape a raw material into a ring during the ringforming sub-method 402. For example, the raw material may be a strip ofmaterial 540 (see FIG. 10) such as aluminum, steel, galvanized steel,coated steel, or other materials which can be advanced from a coil ofthe raw material. In the illustrated embodiment, the ring forming device500 is connected to a roll forming machine 502 to utilize rotation of ashaft 504 of the roll forming machine 502. In another embodiment (notshown), the ring forming device 500 may be a stand-alone device with adedicated drive motor. Returning to FIG. 9, the strip of material 540 isadvanced between feed rollers 506, 508, 510 and into slots 512, 514 on apair of forming rollers 516, 518. The feed rollers 506, 508 and formingrollers 516, 518 are driven to advance the strip of material 540 throughthe ring forming device 500. More specifically, a powered roller drivesthe feed rollers 506, 508. Similarly, a drive shaft 504 rotates a drivegear 520 and the roller 516 which is attached to the drive gear 520.Rotation of the drive gear 520 rotates follower gear 522 and the roller518 connected thereto in an opposite direction. A pair of arms 524, 526hold the rollers 516, 518 relative to one another, with plates 528, 530rigidly fixing the arms 524, 526 together.

The ring forming sub-method 402 begins at step 406 where a raw materialand dimensions of the raw material are chosen. In the illustratedapproach, the raw material is the strip of material 540 having agenerally flat cross-section with a width 542 and a thickness 544 (seeFIG. 10). At step 408 in FIG. 8, the strip of material 540 is advancedinto the ring forming device 500, as shown in FIG. 10. The strip ofmaterial 540 has a center line 546 extending between central axes 548,550 of the forming rollers 516, 518 as the strip of material 540 is fedthrough the rollers 506, 508, 510. To adjust the radius of the ringproduced from the strip of material 540, the ring forming device 500includes a radius adjustment device 552 that adjusts the position of thearms 524, 526 above a base 554 of the device 500. The radius adjustmentdevice 552 comprises a threaded bolt (not shown) and a nut 551 engagedwith threads of the bolt. The plate 528 rests upon the threaded boltsuch that rotation of the nut 551 advances/retracts the bolt relative tothe base 554 and elevates/lowers the arms 524, 526 a distance 556 abovethe base 554.

Adjusting the distance 556 between the arms 524, 526 and the base 554rotates the arms 524, 526 and the roller 518 about the central axis 548of the roller 516. By adjusting the position of the arms 524, 526, theangle at which the roller 518 bends the strip of material 540 can beadjusted. More specifically, rotating the arms 524, 526 counterclockwiseabout the axis 548 decreases the radius of the ring produced from ringforming device 500. Conversely, rotating the arms 524, 526 clockwiseabout the axis 548 increases the radius of the ring.

With reference to FIG. 10, rotating the arms 524, 526 tends to bring thecentral axis 550 of the roller 518 closer to the centerline 546 of thestrip of material 540. Stated differently, rotating the arms 524, 526counterclockwise about the axis 548 moves the roller 518, decreasesdistance 558, and increases distances 566, 568. This causes the strip ofmaterial 540 to strike the roller 518 closer to the equator of theroller 518 and bend at a relatively sharp angle away from the roller518. Conversely, rotating the arms 524, 526 clockwise increases thedistance 558 and decreases the distances 566, 568. This causes the stripof material 540 to strike the roller 518 farther from the equator of theroller 518 and bend at a relatively softer angle away from the roller518.

In the illustrated embodiment, the rollers 506, 508, 510, 516 of thering forming device 500 do not change position as the radius adjustmentdevice 552 is used to adjust the position of the arms 524, 526. Giventhe stationary nature of the rollers 510, 516, rotating the arms 524,526 does not change the distances 560, 563, 564. In alternativeembodiments of the ring forming device 500, the positions of one or moreof the rollers 506, 508, 510, 516 may be adjustable in combination with,or in place of, movement of the roller 518.

In addition to the radius adjustment device 552, slot depths 570, 572,574, 576, 578 of the feed rollers 506, 508, 510, 516, 518 also controlthe radius of the ring produced from the strip of material 540, as shownin FIG. 10. The slot depths 570, 572, 574, 576, 578 are selected toposition a predetermined amount of the width 542 of the strip ofmaterial 540 within the slots 512, 514 of the rollers 516, 518. Further,the slots of the rollers 506, 508, 510, 516, 518 are sized toaccommodate the thickness 544 of the strip of material 540. In oneapproach, the width 542 of the strip of material 540 received within theslot 514 as the material 540 passes through the roller 518 is in therange of between approximately 20% and 90% of the total width 542. Thisengagement between the roller 518 and the strip of material 540 tends tolimit flexing of the strip of material 540 as the strip of material 540advances through the ring forming device 500.

At step 410 in FIG. 8, the strip of material 540 is advanced toward theslotted rollers 516, 518 until a leading end portion 590 contacts theroller 518 and curls upward, as shown in FIG. 11. The leading endportion 590 may include a rounded nose 592 and a flat 594 for contactingthe roller 518 and directing the leading end portion 590 upward. In thismanner, the roller 518 acts as a curling shoe to curl the strip ofmaterial 540. Curling the strip of material 540 compresses a radiallyinner portion 596 of the strip of material 540 while tensioning aradially outer portion 598 located across the center line 546.

During step 410 in FIG. 8, the strip of material 540 continues to beadvanced into the ring forming device 500 until the leading end portion590 makes a complete loop and the strip of material 540 forms a ring610, as shown in FIG. 12. The ring 610 can extend in a generally annularconfiguration for greater or less than 360° as desired for a particularapplication. The ring 610 has inner and outer radii 614, 616 and a ringwidth 613 defined between the inner and outer radii 614, 616. Theprocess of bending the strip of material 540 into the ring 610 maycreate a wave in the ring 610 along the ring width 613. To minimize thewaviness of the ring 610, the dimensions of the strip of material 540may be selected to provide a predetermined ratio of the inner radius 614to the width 542 (see FIG. 10). For example, the ratio of the innerradius 614 to the width 542 may be in the range of approximately 0.5:1to approximately 46:1. Further, the dimensions of the strip of material540 may be selected to provide a predetermined ratio of the outer radius616 to the width 542. For example, the ratio of the outer radius 616 tothe width 542 may be in the range of approximately 2.5:1 toapproximately 48:1. These ratios can be adjusted to accommodatedifferent thicknesses 544 of the strip of material 540, as well asdifferent materials, chemistries, and material treatments. The followingtable presents exemplary ratios for several products having a ten-inchouter diameter:

Ratio of Ring Ratio of Ring Inner Radius Outer Radius Type of Product toStrip Width to Strip Width Forward Curved Wheel 18:1 20:1 Forward CurvedStrip Wheel 38:1 40:1 Backward Inclined Wheel 0.5:1  2.5:1  BackwardCurved Wheel 0.5:1  2.5:1  Mixed Flow Wheel  8:1 10:1 Orifices and InletRings  3:1  5:1

Continued advancing of the strip of material 540 into the ring formingdevice 500 produces a helix 620 at step 410, as shown in FIG. 13. Thehelix 620 wraps around a center axis 612 and is directed to the side ofthe ring forming device 500. At step 412 in FIG. 8, the ring 610 is cutfrom the helix 620 and at step 414, mating ends of the ring 610 areformed. Steps 412 and 414 may be combined such that cutting the ring 610from the helix 620 forms one or both of the mating ends of the ring 610.For example, as indicated in FIG. 13, the ring 610 may be cut from thehelix 620 by creating bevel cuts along paths 622, 624 so that ends 626,628 of the ring 610 can be flush with one another after the ring 610 isremoved from the helix 620. Other approaches may be used to remove thering 610 from the helix 620, such as using a radial cut. In oneapproach, the strip of material 540 continues to be advanced into thering forming device 500 to generate a larger helix 620 with severalrings 610 before the helix 620 is separated from the strip of material540. The rings 610 may then be cut from the helix 620.

At step 416 in FIG. 8, the mating ends 626, 628 are optionally joinedtogether using, for example, a YAG laser-welding procedure. As shown inFIG. 13A, the ring 610 has mating ends 626, 628 joined together at aweld 630. Joining the mating ends 626, 628 of the ring holds the ring610 in an annular configuration and provides a rigid structure forsubsequent processes, such as for connecting the fan blades 26 to thering 610. For some applications of the ring 610, such as an orifice fora blower housing assembly, the mating ends 626, 628 need not be joinedtogether.

The mating ends of the ring may be joined together using alternativeapproaches, such as spot welding, parent metal fastening, or mechanicalfasteners. For an approach such as spot welding, the ring 610 may belonger than 360° so that there are overlapping portions of the ring 610that can be spot welded together. For example, the ring 610 may have endportions 632, 634 that overlap and are joined at a spot weld 636, asshown in FIG. 13B. If the ring 610 with overlapping portions 632, 634 isused in a fan assembly application, such as for the hub ring 22 of thefan assembly 10 (see FIG. 1), it is preferred to utilize at least oneother ring 610 with overlapping portions in the fan assembly 10, such asthe end rings 28 and 30, to evenly balance the fan assembly 10. Morespecifically, the overlapping portions 632, 634 of the rings 610 arespaced evenly around the fan assembly 10, i.e., the overlapping portionsof the hub ring 22 and end rings 28, 30 would each be separated byapproximately 120° from one another around the circular profile of thefan assembly 10. Weights or other corrective measures could be thenapplied to the fan assembly 10 to balance the fan assembly 10 after theblades 26 have been installed.

At this point, the completed ring 610 enters the finishing sub-method404 of FIG. 8, which will be described in greater detail with respect toFIGS. 1 and 14-16. If the final product is to be a venturi or orifice atstep 418 in FIG. 8, the shape of the orifice may be formed at step 420.The orifice can be utilized on mixed flow fans, blower housing inlets,backward inclined centrifugal fan assemblies, and backward curvedcentrifugal fan assemblies, to name a few applications. In one approachthe ring 610 can be formed into an orifice 700, shown in FIGS. 14 and15, at step 420 in FIG. 8. The ring 610 can be formed into an orifice700 using spinning or forming in a die. The orifice 700 includes ends702, 704 that correspond to the ends 626, 628 of the ring 610 in FIG.13. The ends 702, 704 are joined at a weld 706, which was applied atstep 416 in FIG. 8 before the ring 610 entered the finishing sub-method404. The orifice 700 includes a neck portion 708 defining an inlet 710and a flange portion 712 for connecting to the associated fan assembly,blower housing structure, or other component. In another approach, thering forming device 500 simultaneously bends the strip of material 540into the ring 610 and forms features of an orifice into the ring 610such that a substantially complete orifice 700 exits the ring formingdevice 500. In this approach, the rollers 506, 508, 510, 516, 518 areconfigured to impart the desired curvature of the orifice 700, such asthe neck portion 708, as the strip of material 540 is advanced throughthe ring forming device 500. The orifice 700 may be made from galvanizedsteel, aluminized steel, aluminum, or stainless steel, among othermaterials.

If the ring 610 is to become an end ring at step 422 in FIG. 8, the ring610 may be shaped at step 424. For example, the end ring 28 of the fanassembly 10 in FIG. 1 may not require additional forming. By contrast, abackward inclined centrifugal fan assembly 800, as shown in FIG. 16, hasan end ring 802 with an integral orifice 804 formed using a die press orother forming method at step 424. The forming of the orifice 804 intothe end ring 802 is one example of the shaping that may occur at step424 in FIG. 8. Like the orifice 700, the end ring 802 has ends 806, 808that correspond to the ends 626, 628 of the ring 610. The ends 806, 808are joined at a weld 810, or other joining method, which was applied atstep 416 in FIG. 8 before the ring 610 entered the finishing sub-method404.

At step 426 in FIG. 8, attachment points for connecting fan blades tothe end ring are added to the end ring. For example, slots may be formedin the end ring if the end ring is similar to the end ring 28 of the fanassembly 10. For the end ring 802 of the fan assembly 800, rivets 812are used to connect a plurality of blades 814 to the end ring 802.

If the ring 610 is to become part of a hub assembly at step 428 in FIG.8, the ring 610 is used as a hub ring and shaped at step 430 if needed.Further, fan blade attachment points may be formed on the hub ring atstep 430. A hub assembly produced at step 428 using the ring 610 mayreplace a back disc for, among other applications, a forward curvedsingle inlet centrifugal fan assembly, a backward inclined centrifugalfan assembly, a backward curved centrifugal fan assembly, and a mixedflow fan assembly. A centrifugal fan assembly produced using the ring610 may be any type of centrifugal air moving device having forwardcurved blades or other blade configurations. Similarly, a hub assemblyproduced using the ring 610 can replace a central disc for, among otherapplications, a forward curved double inlet centrifugal fan assembly oran end disc for a forward curved tangential fan assembly.

For example, the ring 610 may be used as a hub ring 22 of the fanassembly 10 with a minimal amount of shaping and the addition of slots24 at step 430. Similarly, the ring 610 may be used as a hub ring 824 ofthe fan assembly 800 with minimal shaping and the addition of holes toreceive rivets 813 which secure the plurality of blades 814 to the hubring 824. As shown in FIG. 16, ends 826, 828 of the hub ring 824correspond to ends 626, 628 of the end ring 610.

At step 432 in FIG. 8, one or more hub strips for joining to the hubring may be stamped from a coil of material, such as hub strips 18, 20of the fan assembly 10 or the hub strips 820, 822 of the fan assembly800. At step 433, the one or more hub strips may be shaped, such asshaping the hub mounting portions 90, 98 of the hub strips 18, 20 of thefan assembly 10 (see FIG. 4). By contrast, the hub strips 820, 822 areillustrated in FIG. 16 without mating portions, such that shaping thehub strips 820, 822 at step 433 is unnecessary.

At step 434 in FIG. 8, a hub may be connected to the hub strips, such asconnecting a hub 823 of the fan assembly 800 to the hub strips 820, 822.For rigidity purposes and/or to influence the resonance frequency of afan assembly, the hub strips 820, 822 may be joined together before thehub strips 820, 822 and the hub 823 are connected to the hub ring 824.The hub strips 820, 822 may be joined together using welds, rivets, orother approaches. In some applications of the method 400, the step 434is not performed, such as when the hub 823 is integrally formed with oneof the hub strips 820, 822. Further, the step 434 may be omitted when afan assembly does not utilize a hub, such as when the hub strips 820,822 have a mounting point or feature for direct attachment to a shaft orclamp.

At step 436 in FIG. 8, the attachment portions of the hub strips areconnected to the hub ring. For example, the tabs 60, 62 of the hub strip18 (see FIG. 3) are spot welded or joined by some other method to thehub ring 22. The hub strip 820, by contrast, has attachment portions830, 832 connected to the hub ring 824 using rivets 834.

Returning to FIG. 8, if the ring 610 is to be used for a product otherthan an orifice, an end ring, or a hub assembly, the ring 610 goes on tosubsequent processing at step 438 to produce the desired product.

It will be understood that various changes in the details, materials,and arrangements of parts and components which have been hereindescribed and illustrated in order to explain the nature of the fanassembly and method may be made by those skilled in the art within theprinciple and scope of the fan assembly and method as expressed in theappended claims. Furthermore, while various features have been describedwith regard to a particular embodiment or a particular approach, it willbe appreciated that features described for one embodiment also may beincorporated with the other described embodiments.

What is claimed is:
 1. A method comprising: bending a member into anannular configuration; joining end portions of the member together torigidly fix the member in the annular configuration and form a rigidannular member having an opening with a center; positioning at least onehub strip relative to the rigid annular member; directly connecting atleast one attachment portion of the at least one hub strip to the rigidannular member so that the at least one attachment portion contacts therigid annular member and the at least one hub strip extends beyond thecenter of the opening of the rigid annular member; and connecting aplurality of blades to the rigid annular member.
 2. The method of claim1 wherein positioning at least one hub strip includes positioning a pairof elongate hub strips in overlapping relation with one another withlengths of the hub strips extending transversely to one another.
 3. Themethod of claim 2 wherein connecting at least one attachment portionincludes connecting at least one attachment portion of each of the pairof hub strips to the rigid annular member.
 4. The method of claim 1wherein the member is a strip of material and bending the member into anannular configuration includes advancing the strip of material from acoil.
 5. The method of claim 1 wherein bending the member into anannular configuration includes bending the member along a longitudinaledge of the member.
 6. The method of claim 1 wherein bending the memberinto an annular configuration includes bending the member into a helixand cutting an annular section from the helix.
 7. The method of claim 1wherein bending the member into the annular configuration includesbending the member to have an inner radius such that the member has aratio of the inner radius to an initial width of the member in the rangeof approximately 0.5:1 to approximately 46:1.
 8. The method of claim 1wherein bending the member into the annular configuration includesbending the member to have an outer radius such that the member has aratio of the outer radius to an initial width of the member in the rangeof approximately 2.5:1 to approximately 48:1.
 9. The method of claim 1wherein joining end portions of the member includes joining the endportions such that the end portions are flush with one another.
 10. Themethod of claim 1 wherein joining end portions of the member includesjoining the end portions such that the end portions overlap one another.11. The method of claim 1 wherein connecting at least one attachmentportion of the at least one hub strip includes connecting a pair ofattachment portions disposed on opposite sides of a body portion of thehub strip to the rigid annular member.
 12. The method of claim 1 furthercomprising connecting a hub to a body portion of the at least one hubstrip.
 13. A method comprising: bending a first flat member having apair of edges that are straight into an annular configuration whereinthe edges are annular; joining end portions of the first member togetherto rigidly fix the first member in a substantially flat, annularconfiguration; connecting at least one attachment portion of at leastone hub strip to the first substantially flat, rigid annular memberhaving annular edges; and connecting a plurality of blades to the firstsubstantially flat, rigid annular member having annular edges.
 14. Themethod of claim 13 further comprising: bending a second member into anannular configuration; joining end portions of the second membertogether to rigidly fix the second member in the annular configuration;and connecting the plurality of blades to the second rigid annularmember.
 15. The method of claim 14 further comprising advancing thefirst and second members from at least one coil.
 16. The method of claim15 wherein advancing the first and second members from at least one coilincludes advancing the first member from a first coil and advancing thesecond member from a second coil.
 17. The method of claim 16 wherein thefirst member has a width and the second member has a width smaller thanthe width of the first member.
 18. The method of claim 14 furthercomprising: bending a third member into an annular configuration;joining end portions of the third member together to rigidly fix thethird member in the annular configuration; and connecting the pluralityof blades to the third rigid annular member.
 19. The method of claim 18wherein connecting the plurality of blades to the first rigid annularmember includes embossing at least one blade to restrict movement of thefirst rigid annular member along the at least one blade.
 20. The methodof claim 18 wherein connecting the plurality of blades to the firstrigid annular member includes advancing an intermediate portion of atleast one of the plurality of blades into a slot of the first rigidannular member in a direction generally radially inward relative to thefirst rigid annular member.
 21. The method of claim 13 furthercomprising connecting a hub to the at least one hub strip.
 22. Themethod of claim 13 further comprising separating the at least one hubstrip from a coil of material.